And it couldn't come at a more opportune time. Before the splashy news on Wednesday, the 22 cannabis companies tracked by industry expert Echelon Wealth Partners traded on an enterprise value to 2019 projected EBITDA of 14.4 times. That's well off the sector peak multiple of 22.4 times notched in Oct. 2017 as investors questioned valuations and ongoing regulatory battles in the U.S.

But with Constellation plunking down a 51% premium to up its stake to 38% from 10% in Canopy Growth, cannabis stocks have good reason to retest peak valuation levels.

Says Echelon Wealth Partners analyst Russell Stanley:

"In our view, the key takeaway from this development is that cannabis is quickly becoming a truly global business. We believe the recent softness in the cannabis sector can be attributed to a focus on the outlook for the Canadian market (tempered product pricing expectations, the retail pivot in Ontario), to the exclusion of opportunities outside of Canada. We view the Canopy/Constellation news as further proof that a global market opportunity awaits, with Canadian-listed companies well positioned to participate given their head start and superior access to capital."

Here is quick look at Stanley's cannabis coverage universe. Start here if you are searching for a way to invest in the space.